In recent years, electronic devices such as cellular telephones and the like are rapidly becoming more compact yet capable of ever higher performance. Along with that, the electronic components used in such electronic devices are also rapidly becoming increasingly compact. However, a drawback is that the voltage endurance of electronic devices and components is decreasing along with that trend for devices to become more compact. As a result, there has been an increase in cases where electrical circuits in the devices are damaged by static electric pulses that are generated when there is contact between the human body and terminals in the electronic device. This is because a high voltage on the order of several hundred- to several kilo-volts is applied by that static electric pulse to the electrical circuit in the device at an ultra-short amount of time of 1 nanosecond or less.
Conventionally, as a countermeasure against such static electric pulses, a method has been implemented that provided a countermeasure component between a line for entry of static electricity and a ground. On the other hand, in recent years, because of the increased speeds for data transmission and reception, signal frequencies of signal lines are increasing to result in the transmission speeds of several hundred Mbps or higher. Along with that, it is preferred that the stray capacitance of the static electricity countermeasure components above be as low as possible in order not to deteriorate the quality of signals transmitted at high speed. Therefore, in case where data is transmitted at speeds higher than several hundred Mbps, a static electricity countermeasure component of low static electric capacitance of 1 pF is required.
As a static electricity countermeasure on a high-speed line, Japanese Unexamined Patent Publication (Kokai) No. 2002-538601, for example, proposes a static electricity countermeasure component of a type that fills an over-voltage protection material between opposing gap electrodes.
As proposed in Japanese Unexamined Patent Publication (Kokai) No. 2002-538601, in the static electricity countermeasure component of the type that fills over-voltage protective material between opposing gap electrodes, a discharge current flows between conductive particles or semi-conducting particles dispersed in the over-voltage protective material that is an insulating material between the opposing gap electrodes when over-voltage by static electricity is applied between the opposing gap electrodes. Static electricity countermeasures are attempted by bypassing that discharge current to a ground as a current.
However, in this type of the static electricity countermeasure component, when the voltage applied by the static electricity becomes higher, the discharge current between the conductive particles generates sparks which can jump beyond the over-voltage protective material in some cases. The resin used in this over-voltage protective material is a silicone-based resin, so although it possesses good tolerance of voltages and durability against heat, its hardness and weather resistance performance are inferior. For that reason, epoxy resin or phenol resin are often used in the outermost protective resin layer. However, these resins have inferior voltage tolerance and heat resistance compared to the silicone-based resin, so if discharge sparks is generated and reach the outermost protective resin layer, the resin may carbonize thereby increasing the possibility of causing insulation deterioration. Therefore, it was difficult with the conventional static electricity countermeasure component to prevent the insulation deterioration caused by static electric pulses.